Two people have reportedly been killed in armed clashes between supporters of a pro-Hezbollah group and followers of a Sunni cleric in south Lebanon, local media has said.

The fighting erupted in the Abra neighbourhood of the port city of Sidon on Tuesday, as the army cut off roads leading to Abra in an effort to control the fighting there, state news agency NNA said.

It is the latest apparent outbreak of violence between Lebanese factions supporting opposing sides in the civil war in neighbouring Syria.

Lebanon's Sunni leaders have called on their followers to fight alongside Syria's rebels, who are mostly Sunni. While the Shia group Hezbollah has given its support firmly to the Syrian President Bashar al-Assad.

Automatic rifles and rocket propelled grenades were used in the fighting in the eastern Sidon suburb, marking the worst violence in the area in years.

'Hezbollah apartments'

Sheik Ahmad al-Assir, the Sunni cleric whose followers were fighting in Sidon, is a vehement critic of the Hezbollah and has threatened to clear apartments occupied by the group's supporters in the mostly Sunni city.

Al Jazeera's Nour Samaha, reporting from Beirut, said Assir has made repeated accusations that there were Hezbollah apartments in the area near his mosque that the cleric wants cleared.

"Following the clashes today, he told one local channel that he has given the tenants of these apartments a deadline until Monday to get out," Samaha said.

Local media reported that the gunmen fighting Assir's followers belonged to the local Resistance Brigades that support Hezbollah.

Tensions have been building in Sidon since Monday, when followers of Assir said a soldier verbally harassed one of them as he went to the local mosque to pray.

The clashes erupted on Tuesday after several people attacked the car of Amjad al-Assir, the brother of the cleric, throwing stones at his car and breaking its glass, the officials said.

The army issued a stern ultimatum calling on all gunmen in the area to get off the streets, saying they will open fire on any armed man they see, our correspondent said.